Turbine driven pump means



June 19, 1956 T. w. JOHNSON 2,750,892

TURBINE DRIVEN PUMP MEANS Filed Nov. 13, 1952 INVENTOR.

THOMAS W JOHNSON M g k HITOR/VEY United States Patent C) TURBINE DRIVEN PUMP MEANS Thomas W. Johnson, Westfield, N. .l., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application November 13, 1952, Serial No. 320,253

2 Claims. (Cl. 103-87) The present invention relates to turbine and pumping means and more particularly to those means employed in a jet engine.

A jet engine derives its thrust from its exhaust gases which are discharged from the tail pipe into the atmosphere with great velocity. It has been found that the aforesaid thrust of the engine may be materially increased by burning fuel in the tail pipe of the engine. The means for supplying the fuel to be burned in the tail pipe of the engine, generally known as afterburner mechanism, usually includes one or more nozzles disposed in the tail pipe and suitable pumping means for pumping the fuel from the fuel supply to the nozzle or nozzles.

It has been found that in instances where the fuel pumping means include a turbine for operating the pump, that sporadic delivery of the fuel to the pump inlet results in unloading the same and consequently the pump tends to over-speed to a condition known as running away. In certain instances, for example, where turbine speed is relatively high, this running away of the pump has resulted in its destruction.

One object of the present invention is to provide a combined turbine and fuel pump adaptable for supplying fuel to the afterburner nozzles of a jet engine, and which is constructed and arranged to prevent destructive overspeeding or running-away of the turbine.

Another object of the instant invention is to provide means of the above indicated character wherein the number of moving parts shall be a minimum.

Still another object of the invention is to provide a combined air driven turbine and pump which shall be compact, light, easy to manufacture and install, and yet strong, durable, and extremely reliable in operation.

The foregoing and other objects and advantages will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not to be construed as defining the limits of the invention.

In the drawing, which is a longitudinal section of the novel turbine driven pump contemplated herein, a housing comprises an endsection 12, and center sections 14 and 16, secured as by bolts 18. A driving fluid inlet in the end section 12 leads by means of a passageway 22 to a series of nozzles 24 thence to the first stage 26 of an impulse type turbine 28. A series of fixed blades 30 lie intermediate the first stage 26 and a second stage 32 of the turbine 28. An exhaust opening 34 communicates with the second stage 32 of the turbine 28.

A male shaft 36 and a female shaft 38 protrude from opposite ends of the turbine 28. The male shaft 36 rests in the inner race of the bearings 40 which in turn are housed in a bearing retainer 42.

The female shaft 38 on the opposite end of the turbine 28 is internally threaded to accommodate a threaded drive shaft 44 of an impeller 46 of a centrifugal fuel pump 48 Patented June 19, 1955 to thereby operatively connect turbine 28 to pump 48.. The centrifugal pump 48 is of a type well known in the art. The shaft 38 supplies the rotary power to drive the pump 48 through the threaded drive shaft 44.

An inlet 50 of the pump 48 is mounted by bolts 52 to an end of section 16 and is adapted to be connected to a suitable source of liquid, such as a fuel supply (not shown). Inlet 50 leads, by means of a conduit 54, to a hollow impeller shaft 56 which forms the front section of pump 48 and which rides in an impeller bearing 58.

An impeller chamber 60 connects impeller 46 to a pump discharge port 62. Suitable seal means including pressure seal 66 and 0 rings 68 and 70 are provided to prevent leakage from the pump section of the housing 10 to the turbine 28.

Having thus described the invention, in operation, it will now be apparent to those skilled in the art that when the inlet 20 is connected to a suitable source of driving fluid, as for example, the compressor of a jet engine, the fluid so admitted will pass along the passageway 22, through the nozzles 24 where it will be directed to the first stage 26 of the turbine 28 to impart rotary motion to the turbine. Thence the fluid will pass through the fixed blades 30 which will direct it toward the second stage 32 and the fluid will then exhaust to the ambient atmosphere through the exhaust opening 34.

The energy so drawn from the driving fluid by the turbine 28 serves, by means of the shaft 38, to turn the impeller 46 of the centrifugal pump 48 thereby drawing fuel from the inlet 50, along the conduit 54 and into the impeller 46 where it is radially expelled to the impeller chamber 60 and the pump outlet 62 and thence to the afterburner nozzles not shown here.

It is well known that the terminal velocity of a single stage turbine unit is greater at running away conditions than the terminal velocity of a multistage turbine unit under the same conditions. This is due to the fact that the terminal velocity of a multistage turbine unit occurs at a substantially lower ratio of turbine wheel peripheral velocity to driving fluid velocity than in a single stage turbine unit. The foregoing characteristics of turbines is more fully set forth in Steam and Gas Turbines, vol. 1, by Dr. A. Stodola, as reprinted by McGraw-Hill Book Co., New York, 1945.

Therefore, by utilizing a multistage turbine unit to drive the fuel pump, the terminal velocity of the turbine will be held at a relatively low value to the end that the possibility of a destructive running away is eliminated in the event that the fuel supplied to the impeller of the pump is sporadically interrupted while the driving fluid remains fully effective. In other Words, due to the foregoing construction and arrangement of parts, in the event the fuel delivered to inlet 54 and hence impeller 46 of pump 48 is diminished below a predetermined value, or sporadically interrupted, thereby resulting in the unloading of pump 48, the speed of turbine 28 will increase until it reaches its terminal velocity and will remain there until normal fuel supply is reestablished or, in the alternative, the driving fluid is shut off.

There are thus provided turbine and pump means for supplying fuel to the afterburner nozzles in a jet engine, that are extremely compact, simple and light and embodying a minimum of moving parts, for the turbine 28, and pump 48, revolve as one integral unit. Moreover,

since turbine 28 is a multistage turbine unit, the possibility of its destructive running away in the event pump.

48 unloads is eliminated.

Although only one embodiment and one application of the invention has been illustrated and described, otherchanges and modifications in the form and relative ar--- rangement of parts, which will be apparent to those skillecL inthe art, may he made without departing from the pi it nd. cope of h inv ntion I claim:

1. A combined turbine pump unit of the character described adapted; for supplying; fuele to theafterburner nozzles of ajet engine, comprisinga unitary.- housingstructure having an axial, pressure air fluid inlet in one end adapted for connection to the-compressor unit of the jet engine and an. axial fuel inlet in the opposite end for.con nection to; a source, of fuel. supply, a two. stage impulse typeturbine wherein the blades. of each stage are axially spacedfromthose of the other and both stages are integral withva commonsbody portion, astub.shaftintegral'with and projecting axially from one end of theturbine' body portion-to a point in close proximity to the pressure air fluid inlet,-. a bearing} support inthe-housing carrying the. stud shaft for rotatable movement thereima series of nozzles in the houSing comrnunicatiugithe first turbine stagewith the pressure air fluid inlet, a fixed turbine stage intermediate of, the. blades of thefirst and-second: stages for guiding pressure air fluid fiowfrom .thefirst turbine stage'to the second-stageand the housing zhaving'an-exhaustport communicating the second turbine stage to atmosphere, a second stub shaft integral with; the turbine body and extending axially from the other end thereof, the latter shaft being recessed in its free end, the. housing havinganimpeller chamber sealedloff-i fromthezturbine stages, afuel" pump impeller positioned in the impeller, chamber, and havinga short axial-shaft portion extending from the inner face thereof and engagedin the recessed, turbine shaft, a hollow shaft'portion integral with the outer face of the impeller and axially communicating theinterior of the impeller with the fuelinlet, the housing including a fuel outletadapted for communicating the imepller chamber with the after-burner nozzles of the jet engine, and

4, bearing means carried in the housing for axially supporting.. tl1e.hollow shaft of the impeller for rotatable movement thereof with the turbine.

2. In a combined turbine pump unit as in claim 1, wherein the housing comprises four separable sections axially aligned and bolted to one another to form a unitary structure, the first section having the axial pressure air fluid inlet, the second section housing the turbine stages, the third sectionihousing: the impeller and the fourth sec tion having the axial fuel inlet, whereby removal of the first and second housing sections exposes the turbine unit for access thereto, and removal of the third section allows access to the impeller.

References Cited inthe file of this patent UNITED STATES PATENTS 1,014,330 Reeve Jan. 9, 1912 1,154,434 Rees Sept. 21, 1915 1,609,306 Peterson fi Dec. 7, 1926 1,894,393 Bigelow Ian. 17, 1933 2,109,997 Hoffman Mar. 1, 1938 2,296,701 Butler Sept. 22, 1942 2,393,691 Karassik' 12111.29, 1946 2,439,127 D'ailey et all Apr. 6, 1948' 2,442,579 Auger" June 1, 1948 2,475,151 Nichols July 5, 1949' 2,475,316: Garraway July 5, 1949 2,480,095' B'uchi" Aug. 23, 1949 2,492,672 Wood Dec. 27, 1949 2,606,501 Dreibelbis' Aug. 12, 1952 FOREIGN PATENTS 250,727",- Switzerland Sept. 15, 1947 877,310 France Sept. 1, 1942 

